Of course the reluctance to study this subject (the cited research only started in 1980) has nothing to do with the fact that the Govt here owns much of the tobacco industry and gets a lot of income from it (indeed that is explicitly the purpose of maintaining ownership).

Fortunately, attitudes towards smoking are changing rapidly here. When we first arrived, no-smoking areas were few and far between (and pretty meaningless, given the absence of any sort of separation from smoking areas). Now they are more and more common, and there are increasingly restrictions on smoking in public. It's been quite a turnaround, in fact. Who says the Japanese are conservative and cannot change?